1. Field of the Invention
This invention relates to a circuit breaker having a unitary actuating shaft with rotating movable contacts in alignment with stationary contacts, and an arc shield rotatable with the shaft and contacts thereon.
2. Description of the Prior Art
A switch of the "quick-make and quick-break" type is suitable for distribution transformers where the switch contacts are immersed in transformer oil. Such switches are disclosed in U.S. Pat. Nos. 3,461,259 and 3,590,183 and are provided with an overcenter spring mechanism for rotatably moving contact structures for opening and closing circuits. The rotatably movable contact structure comprises a contact carriage carrying pairs of contact fingers extending outwardly from the carriage, and making separable engagement with corresponding stationary spaced blade-type contacts.
A problem with this type of switch is that it is limited in its current interruption capabilities by the amount of arc quenching and insulating medium-transformer oil between the moving contacts and the stationary contacts in their open position. An obvious method for increasing the current interruption capacity would be to increase the physical size of the switch, thereby increasing the distance between the contacts. However, increased size requires increased inertia of the contact rotor, thus increasing the size of the operating mechanism.